1855-S $3 PR64 Cameo NGC. CAC. Ex: Golden Gate Collection.
The 1848 discovery of gold in California forever changed the region
and the nation. The Western population quickly swelled with
prospectors, and a scarcity of coinage made life extremely
difficult. Gold dust was the medium of exchange in California, and
the individual prospectors typically received less than half its
real value. One option was to ship the gold dust to the mints in
New Orleans or Philadelphia, where pure dust was worth at least $16
per ounce. However, payment of express charges, commissions, and
insurance substantially reduced the net value. Another option was
to sell the dust to local bankers who also substantially discounted
the value, shipping large quantities to New Orleans or
Philadelphia.
Individuals and small companies were soon established in California
to produce coins from the fresh gold supply. In Private Gold
Coins and Patterns of the United States, Donald H. Kagin
writes:

"During our nation's history, the Federal Government
has theoretically been responsible for issuing coinage whenever and
wherever the need existed. Many times, however, when the Federal
Government was slow to meet its responsibilities, private
individuals took it upon themselves to provide alternatives to the
official, but unavailable, coins of our nation."

The private coinage in California was not without its problems,
principally inadequate weight and/or fineness. Eventually the
Federal Government stepped in, opening the United States Assay
Office following Congressional legislation passed on September 30,
1850. The first issues appeared early in 1851, carrying the name of
Augustus Humbert, U.S. Assayer. Authorized by the United States,
the new issues forced most private coiners out of business and
clearly proved advantageous to the individual miners, who would now
receive full value for their gold dust and nuggets. The Assay
Office was a temporary measure; a full-fledged branch of the U.S.
Mint opened in San Francisco in 1854. Kagin writes:

"The United States Assay Office was a reasonable,
although temporary, solution to the need for a standard medium of
exchange, but what the Californians earnestly desired was their own
branch mint. Proposals for a California branch mint appeared as
early as December 1849, but legislation failed until July 3, 1852.
Finally, the San Francisco branch mint officially opened on April
3, 1854."

1854-S Double Eagle Proof
The first double eagle was minted on the opening day, April 3,
1854. Considered a proof or presentation strike, the coin is now
part of the National Numismatic Collection at the Smithsonian
Institution. In Encyclopedia of United States and Colonial Proof
Coins, Walter Breen discussed the 1854-S double eagle:

"When I saw it in 1951, neither Stuart Mosher (then
curator as well as Numismatist editor) nor I had any idea it
was a branch mint coin, and great indeed was our astonishment at
finding the S mintmark. It would have passed as a Philadelphia
proof had I not looked at the reverse."

More recently, Jeff Garrett and Ron Guth published a slightly
different opinion regarding the 1854-S double eagle in their
Encyclopedia of U.S. Gold Coins 1795-1933:

"Although the coin has been called a Proof by most
researchers, it is the authors' opinion that the coin would be more
accurately described as a presentation strike. The surfaces are
deeply prooflike but lack the deep, orange-peel appearance of true
Proofs of the era."

1855-S Three Dollar Proof
When Walter Breen penned his Proof Encyclopedia, published
in 1977, the proof 1855-S three dollar gold was unknown to him. It
made its first public appearance in the 1984 Apostrophe Sale.
Breen's 1989 revision to his earlier work suggests a second proof
example was known to him, but he gave no further details, other
than to say it was in a "private collection." Until such time as
the second piece makes its appearance, this proof 1855-S three has
to be considered unique.
Jeff Garrett purchased the newly discovered gold piece at the 1984
ANA convention and later described it as "a supremely rare Proof
that any serious collector would love to own." Although he writes
in Encyclopedia of U.S. Gold Coins 1795-1834 that the coin
first surfaced at the 1984 ANA convention, it actually appeared
just prior to the convention; it was consigned to Paramount's
session of Auction '84, held the preceding weekend.
The existence of the proof 1855-S three dollar was apparently known
to a few individuals the previous decade. In The United States
$3 Gold Pieces, 1854-1889, Q. David Bowers writes:

"The known example was shown to one of the authors
(Bowers) by John Struzan in the 1970s. It later was acquired by
David Stagg III, who sold it in 1983 to Jimmy Hayes and John
Dannreuther, after which, graded as Proof-63, it appeared in
Paramount's section of Auction '85 [sic] as lot 881 and
later was in several other sales, still as Proof-63, now certified
by NGC."

David Akers, associated with Paramount in 1984, wrote the first
description of the 1855-S proof three dollar piece, the same coin
that is offered today. A keen numismatic observer, then as today,
Akers commented:

"Its proof status is, in our opinion, absolutely
certain and the coin was surely struck to mark the first minting of
the Three Dollar denomination at the San Francisco Mint. ... We
have examined this coin for many hours, comparing it both to
business strikes of the period and to proofs, including an 1855
Philadelphia Mint proof $3. It is totally unlike any business
strike 1855-S $3 in overall appearance and texture (albeit from the
same dies) and it is remarkably similar to the 1855 $3 proofs
struck at the Philadelphia Mint. In fact, if there were no 'S'
mintmark on the reverse, one would immediately take it for an 1855
Philadelphia Mint proof."

The next auction appearances in 1988 and 1990, offering this piece
as PR63 NGC, essentially reprinted the Akers description. In the
January 2000 Rarities Sale, Bowers and Merena offered this 1855-S
proof three dollar piece, now certified PR63 PCGS, according to the
catalog. Little further information was offered about this coin in
the Bowers and Merena catalog.
Akers aptly provided the physical appearance of this proof 1855-S
three dollar gold piece in Auction '84:

"A very attractive, brilliant proof with a 100% full
strike, a sharp, square edge and deep mirror fields that have
considerable 'orange peel.' (This 'orange peel' texture is one of
several characteristics of virtually all 19th Century U.S. proof
gold coins.) The color is a rich greenish-gold and orange. There
are some light hairlines on the surfaces but virtually no contact
marks or abrasions. In front of the face and behind the head there
is the 'porosity' (resulting from double striking and conforming
exactly to the shape of the wreath on the reverse which received
the metal flow) that is seen on almost all proof threes. From the
standpoint of quality and overall appearance, this coin is very
pleasing, better than most 1854 proofs we've seen as well as most
of the 1856 and 1857 proofs."

This piece exhibits every design detail exactly as it appeared in
the dies, with obvious cameo contrast between the lustrous devices
and fully mirrored fields. As others have noted, it has every
outward appearance of a Philadelphia Mint proof, except of course
for the S mintmark on the reverse.
Call it "Supremely Rare" or a "Landmark Rarity," the 1855-S is
unique as a proof and it is arguably the single most important coin
in the present sale. Add its numismatic history, and this specimen
is a must for any serious numismatist.From a Sierra Foothills Estate, according to Walter Breen; David
Stagg III; Jimmy Hayes and John Dannreuther; Auction '84
(Paramount, 7/1984), lot 881 as PR63; Auction '88 (Superior,
7/1988), lot 345 as PR63 NGC; Auction '90 (Superior, 8/1990), lot
1294 as PR63 NGC; The Rarities Sale (Bowers and Merena, 1/2000),
lot 340 as PR63 PCGS; Stack's (10/2004), lot 2025 as PR63
PCGS.(Registry
values: P8) (NGC ID# 289T, PCGS# 8054)